Chemical Enhanced Oil Recovery Research Papers (original) (raw)

Nigeria is gradually advancing into the secondary stage of oil recovery, necessitating preparation for tertiary oil recovery especially enhanced oil recovery (EOR). Considering the high cost of EOR agents, it is imperative to investigate the performance of available local EOR agents against foreign agents when these agents (such as surfactants and polymers) are used in combination. Oil displacement experiments were thus conducted using foreign and local surfactant-polymer (SP) and alkaline-polymer (AP) agents on Nigerian crude and their results were compared. The experiments entailed using different percentage ratios of surfactants to polymers and alkaline to polymer. Four kinds of Alkaline were also used to displace residual oil from sand to find out what type of alkaline displaces oil better. The displacement efficiencies obtained from experimental results showed that the foreign EOR agents performed better than the local EOR agents. For the SP agents, the foreign SP displaced above 90% of both light and medium crude at about 45/55 percentage and 0/100 percentage respectively. The local SP displaced a maximum of about 35% of the light crude and 75% of medium crude at an SP ratio of about 20/80 for both cases. The use of Alkaline-Polymer results showed that the foreign agents performed better than the local agents. The maximum displacement efficiency of the foreign AP was 78.13% at a ratio of 40/60 while the maximum displacement efficiency of the local AP was 64% at a ratio of 60/40. The displacement of residual oil experiments performed using four kinds of alkaline showed that potassium hydroxide (KOH) enhances recovery better than NaOH, Na 2 CO 3 and Palm bunch ash (a local source of alkaline). It was also observed that oil displacement efficiency increased as pH value of the alkaline increased.

This work investigates the use of polymers during CO 2 WAG using a physical model. Coreflooding experiments were conducted to compare polymer assisted WAG, conventional WAG, continuous CO 2 flooding, and polymer flooding. The effect of miscibility in the CO 2 – oil interface was evaluated from coreflooding at two different pressures, above and below the MMP of 1563 psig The MMP was experimentally determined using a fast version of the slim tube procedure with a shorter column. The influence of reservoir heterogeneity was observed by conducting corefloodings in homogeneous and heterogeneous rocks with permeability ranging from 13 to 1300 md. The core plugs were selected using computed tomography to ensure the presence or absence of heterogeneous features. Our results show that under miscible displacement in a homogeneous rock, continuous CO 2 injection can reduce residual oil saturation (S or) to less than 10%, even for a permeability as low as 13 md. The implementation of conventional WAG and polymer assisted WAG in this case was detrimental for the process as water saturation shielded a portion of the oil preventing CO 2 contact. The departure from the ideal miscible displacement resulted in a S or as high as 32 %. For the heterogeneous rock, at 285 psig above MMP, the WAG CO 2 was able to reduce S or to as low as 11%, whereas at 260 psig below MMP a S or of 23% was reached. As the level of heterogeneity increases, the oil recovery of polymer assisted WAG relative to conventional WAG increased suggesting that a certain degree of heterogeneity is needed for the polymer assisted WAG process to be beneficial. A throughout discussion on the recovery mechanisms and the interactive / combined role of miscibility, heterogeneity, permeability and viscosity is presented. This work adds to the understanding of the CO 2 flooding process implemented in the North Burbank Unit (NBU) and the potential to use WAG and polymer assisted WAG to improve mobility control. Sweep efficiency is the most important challenge from a reservoir engineering standpoint for CO 2 flooding, but it is particularly critical in the NBU for two reasons. The high vertical heterogeneity in the field, with a permeability variation of three orders of magnitude within 30 ft of reservoir thickness, which greatly exacerbates viscous fingering, and the use of anthropogenic CO 2 which makes the economics of the project more sensitive.

- by Francisco Tovar and +1
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- Enhanced Oil Recovery, Polymer Flooding, Chemical Enhanced Oil Recovery, Naturally fractured reservoirs

Coiled tubing (CT) has been recently applied for frequent drilling operation. Pushing the limits for coiled tubing drilling to include extended reach drilling is opposed by hole cleaning issues. Hole cleaning problems are claimed to be critical in coiled tubing drilling due to lack of drillpipe rotation. This paper is intended to show how significant is the effect of not rotating the inner pipe on hole cleaning during coiled tubing drilling. The drillpipe was constrained at its ends only allowing it to exhibit eccentricity at the mid-section. This allows to simulate the whirling motion of the drillpipe which is claimed to add to good hole cleaning. The effect of pipe rotation was studied and the data collected were graphically correlated in the form of weight percent of recovered particles versus hole inclination at different drillpipe rotational speeds and annular fluid velocities. Results showed that pipe rotation significantly improve hole cleaning; up to 68% improvement was recorded for intermediate velocities (1.86 ft/sec & 2.29 ft/sec). The effect of pipe rotation is less significant at lower annular velocities and lower inclinations (1.43 ft/sec and 60 degree from vertical respectively); however, it has a significant effect at intermediate annular velocities but this effect is diminished with further increase in velocity. The results emphasized that turbulent flow are critical for cuttings removal at horizontal/highly deviated wellbores.

- by Mazen Moherey and +1
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- Multiphase Flow, Crude Oil Drilling Waste - Drill Cuttings, Directional Drilling, Chemical Enhanced Oil Recovery

Recently, natural surfactants had been studied for chemical enhanced oil recovery as opposite to synthetic surfactants due to environmental problems associated with synthetic surfactants. In this study a new plant based natural surfactant, Matricaria chamomilla, is introduced. For this purpose, the interfacial tension values between natural surfactant solution and oil are measured by using the pendant drop method. The results show that Matricaria chamomilla decreased the oil-water interfacial tension values from 30.63 to 12.57 mN/m. Results confirm surface chemical activity of Matricaria chamomilla in comparison with other natural surfactants.

- by soheil shadizadeh and +1
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- Reservoir Engineering, Chemical, Oil and gas, Enhanced Oil Recovery

In this paper, a 3D filtration law for power-law fluids flowing in heterogeneous porous media is derived through stochastic homogenisation. The filtration equation for isotropic porous media is first considered, at the local Darcy-scale. This equation possesses a single flow parameter, which depends on the space variables. The spatial variation of this parameter is modelled by a stationary random field and therefore arbitrarily heterogeneous and anisotropic in character. The stochastic homogenisation technique is then applied for averaging the interplay between rock and fluid parameters. A simple analytical and tractable formula is derived which expresses the importance of both rheological and porous medium related parameters on the mean flow. In order to validate the formula, comparisons are made with numerical experiments for 2D flows. The new law is found to be in good agreement with numerical experiments.

- by Ali FADILI
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- Fluid Dynamics, Porous Media, Chemical Enhanced Oil Recovery, Non-Newtonian Fluids

One of the unanswered issues with steam applications is the wettability state during the process. Removal of polar groups from the rock surface with increasing temperature improves water wettability; however, other factors, including phase change, play a reverse role on it. In other words, hot water or steam will show different wettability characteristics, eventually affecting the recovery. On the other hand, wettability can be altered using steam additives. The mechanism of these phenomena is not yet clear. The objective of this work is to quantitatively evaluate the steam-induced wettability alteration in different rock systems and analyze the mechanism of wettability change caused by the change of the phase of water and chemical additives. Heavy-oil from a field in Alberta (27,780 cP at 25°C) was used in contact angle measurements conducted on mica, calcite plates, and rock pieces obtained from a bitumen containing carbonate reservoir (Grosmont). All measurements were conducted a...

- by randy pratama
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- Materials Science, Reservoir Engineering, Nanomaterials, Nanotechnology

When considering the wettability state during steam applications, we find that most issues remain unanswered. Removal of polar groups from the rock surface with increasing temperature improves water-wettability; however, other factors, including phase change, play a reverse role. In other words, hot water or steam shows different wettability characteristics, eventually affecting the recovery. Alternatively, wettability can be altered using steam additives. The mechanism of this phenomenon is not yet clear. The objective of this work was to quantitatively evaluate the steam-induced wettability alteration in different rock systems and analyze the mechanism of wettability change caused by the phase change of water and by chemical additives. Heavy oil from a field in Alberta (27,780 cp at 25°C) was used in contact-angle measurements conducted on quartz, mica, calcite plates, and rock pieces obtained from a bitumen-containing carbonate reservoir (Grosmont). All measurements were conducte...

- by randy pratama
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- Materials Science, Reservoir Engineering, Nanomaterials, Nanotechnology

A new surfactant 4-((4-bromophenyl)(dodecyl) amino)-4-oxobutanoic acid with a benzene spacer was synthesized via a novel copper catalyzed cross-coupling reaction. Its structure was confirmed by FTIR, 1 H-NMR, 13 C-NMR and HRMS; its purity was checked by HPLC. Dynamic light scattering and an atomic force microscope showed that it forms an unusual large-diameter premicellar aggregation below the CMC.

- by 明贵陈
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- Chemical Enhanced Oil Recovery

This paper evaluates the relevance of Hele-Shaw (HS) model based linear stability results to fully developed flows in enhanced oil recovery (EOR). In a recent exhaustive study [Transport in Porous Media, 93, 675-703 (2012)] of the linear stability characteristics of unstable immiscible three-layer " Hele-Shaw " flows involving regions of varying viscosity, an optimal injection policy corresponding to the smallest value of the highest rate of growth of instabilities was identified among several injection policies. Relevance of this HS model based result to EOR is established by performing direct numerical simulations of fully developed tertiary displacement in porous media. Results of direct numerical simulation are succinctly summarized including characterization of the optimal flooding scheme that leads to maximum oil recovery. These results have been compared with the HS model based linear stability results. The scope for potential application of the HS model based results to the development of fast methods for optimization of various chemical flooding schemes is discussed. Numerical experiments with more complex flooding schemes in both homogeneous and heterogeneous reservoir are also performed and results analyzed to test the universality of the generic optimal viscous families in a broader setting.